In a method of reading data from a non-volatile memory device, read data is generated based on a word line voltage. The read data includes data read from a plurality of sectors included in the non-volatile memory device. Bad sector data is transferred data based on read data and bad sector information. The bad sector data corresponds to data read from at least one bad sector included in the plurality of sectors. The bad sector information is updated by checking error bits of the bad sector data. The word line voltage is generated based on the updated bad sector information.